Question: OpenCPN works fine with the EV1 without any plugins and without NMEA2000. Any commercial NMEA0183-2000 gateway (actisense/yacht devices/etc) handles the translation. The only thing it can't do is start the autopilot (engage “auto”). Even that, the YDWG-02 will optionally do when it receives the APB sentence. So what is AutoTrackRaymarine for, some peculiar connection type?
Answer: Yes, It is called NMEA2000… It implements the Raymarine proprietary PGNs, so no device doing translation, like the YDWG, is needed. Now that OCPN supports NMEA2000 the AutoTrackRaymarine plugin supports n2k and the Raymarine PGNs (as adding proprietary PGNS of a single vendor is not on any list for the core application). The only difference with O5.8 is we take care of the connection to the NMEA bus for them.
Question: The required PGN's (except for the one that sets auto mode) are not proprietary and should work with any autopilot manufacturer. Using a plugin for a “raymarine remote” that implements changing modes, adjusting course, etc. makes good sense, but the PGN's for supporting track mode are standard and should be in the core, just as the equivalent NMEA0183 sentences are included. I know those things don't all come at once.
Answer: To make the EVO pilot work (or work well if you want) the most important is PGN 126208, which is the general “I can transfer pretty much anything” PGN, which is similar for other vendors. This makes the autopilots a prime example of devices that most benefit from implementation in a plugin with architecture similar to the current Radar plugin (= one implementation of the underlying shared stuff reasonable extendable for the different products). It is better architecture than trying to do this in the OpenCPN core and is much faster to yield usable results.